Swap the boolean logic on copy_acl_config

If the exit code is zero on the diff, that means we did not copy
something. Which means we want to return true if status != 0.

Change-Id: I48130c305af8994977c95f0412aedc0bbb29c1eb
diff --git a/jeepyb/cmd/manage_projects.py b/jeepyb/cmd/manage_projects.py
index f4d832f..7f580cc 100644
--- a/jeepyb/cmd/manage_projects.py
+++ b/jeepyb/cmd/manage_projects.py
@@ -152,7 +152,7 @@
         raise CopyACLException()
 
     status = git_command(repo_path, "diff --quiet")
-    return status == 0
+    return status != 0
 
 
 def push_acl_config(project, remote_url, repo_path, gitid, env={}):